Along with progress of the modern society, importance of personal information identification and personal information security gradually attracts attention of people. A human fingerprint has uniqueness and invariance, and thus, a fingerprint identification technology has the characteristics of high security, high reliability and simplicity and convenience for use, so that the fingerprint identification technology is widely applied to various fields of protecting personal information security, and particularly, the field of mobile terminals, e.g., a mobile phone, a notebook computer, a tablet computer, a digital camera and the like, which has more prominent requirements for information security. Currently, a fingerprint identification function is one of common functions of electronic devices, and has important significance for reinforcing security of the electronic devices, expanding the application range of the electronic devices and the like.
An optical fingerprint identification device is shown in FIG. 1; after light emitted by a light source 100 is transmitted to a finger through a prism 101, the light is reflected by the finger, reenters the prism 101 to be propagated, then reaches a focusing lens 102 and is focused by the focusing lens 102, and then reaches an image processor 103; and an image sensor, e.g., a Charge-Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS) image sensor, is arranged on the image processor 103. Light reflected by valley lines and ridge lines on the finger is different in angle and strength, and thus, after the reflected light is projected onto the image processor 103, a fingerprint image can be formed.
However, in the fingerprint identification device shown in FIG. 1, the prism 101, the focusing lens 102 and the image processor 103 need to occupy a large space; and moreover, a certain distance needs to be set between the imaging prism 101 and the focusing lens 102, and a certain distance also needs to be set between the focusing lens 102 and the image processor 103.